<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>移动端基础</title>
  <link rel="stylesheet" href="index.css">
</head>

<body>
  <h1>二倍图之background</h1>
  <div class="outer">
    <div class="box box1"></div>
    <div class="box box2"></div>
  </div>
  <script src="index.js"></script>
</body>

</html>
